Flexible electronics, or flex circuits, are electronic circuits formed by mounting electronic devices on flexible substrates, such as polyimide or transparent conductive polyester film. Flex circuits can also be screen printed silver circuits on polyester. Flexible printed circuits are made with photolithographic technology. In other examples, flexible foil circuits or flexible flat cables can be manufactured by laminating thin copper strips between two layers of PET coated with a thermosetting adhesive and activated during the lamination process.
Flex circuits can conform to a desired shape and be advantageous in certain situations including (a) tightly assembled electronic packages in which electrical connections are required in 3 axes, (b) electrical connections in which the assembly is required to flex during use, (c) electrical connections between sub-assemblies to replace wire harnesses, and (d) electrical connections in which board thickness or space constraints are limiting factors.